Screw-holding screw driver



Sept. 29,1964 J. M. NEIL SCREW-HOLDING SCREW DRIVER Filed Sept. 8, 1960 Y INVENTOR. .M4155 IVE/.-

TOIPNEES United States Patent C) "ice 3,150,698 SCREW-HOLDING SCREW DRIVER James M. Neil, Oakland, Calif., assigner to HJJ. Company, Oakland, Calif., a partnership Filed Sept. 8, 1960, Ser. No. 54,684 3 Claims. Cl.`14550) The present invention relates to screw-holding screw drivers of the type in which opposed bits are placed in the screw slot or kerf and are cammed apart to engage and hold the screws. It is concerned more particularly with improved bit structures for such screw drivers having improved structural features both for operation, for manufacture, and for assembly of the bits or points in the finished tool.

I have discovered in connection with bits of this type which are spread apart by a pin to cam the points into engagement with the sides of the screw slot, that an improved operation is obtained by anchoring the bits at their butt ends so that any pivoting movement of the bits is controlled from this point, and so that the holding of the bit in position is operative at this point. Also, bits of this character can be made symmetrical about a medial longitudinal line thereof so that no undesirable stresses are set up in the bit during forming in the punch press die which would lead to distortion of the bit during heat treatment and result in misalignment of the bits or points when they are placed in the tool.

It is a general object of the invention to provide a screwholding screw driver which attains the foregoing advantageous results.

Another object of the invention is to provide a bit structure for a screw driver Where the control of the opposed bits is provided at the rearward end of the bits away from the screw-engaging points thereof where the anchoring of the bits in assembled relation is effected.

Otherobjects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof, made with reference to the attached drawings in which:

FIG. l is a fragmentary longitudinal sectional view of a screw-holding driver taken through the working end of the tool and with the tube or handle and the camming pin shown in section, the remaining parts being shown in elevation;

FIG. 2 is an exploded perspective view illustrating the structural relation of the screwdriver bits or points at the butt ends thereof, together with the cooperating rod;

FIG. 3 is a fragmentary enlarged view of the rod and the bit structure taken adjacent the butt end;

FIG. 4 is a fragmentary sectional view taken in the plane indicated by the line 4 4 in FIG. 3;

FIG. 5 is a transverse sectional view taken in the plane indicated by the line 5-5 in FIG. 3;

FIG. 6 is a plan view of one of the bits of a screw driver.

Referring to FIG. 1 there is shown a screw-holding screw driver constructed in accordance with the instant invention including a handle 10 of tubular construction, a rod 11 slidably and rotatably mounted in said handle 10, and having reduced end portion 11a forming a seat for respective bit or points 12. The projecting reduced end 11a of the rod engages a transverse camming pin 13 which is secured in the tube 10 as by riveting and engages respective opposite cam surfaces 12a along the side edges of the respective bits at either side thereof.

Each bit (FIGS. l, 2 and 6) comprises an elongated piece of sheet metal such as steel for example, having in the present embodiment a half cylindrical end or shank portion 12b for embracing the reduced portion 11a of the rod and narrowing and formed inwardly toward the head end to form the cam edges 12a, the head or tip 3,150,698 Patented Sept. 29, 1964 being formed thereafter into a planar bit end 12e suitable to engage the side walls of the kerf of the slotted screw with which it is used.

In order to anchor the bits or points 12 longitudinally with respect to the rod so that they move with it as an assembly in sliding in the tube 10, each of the bits includes symmetrically disposed anchoring means located at the butt end thereof which is formed inwardly from the adjacent semi-cylindrical shank portion of each bit so as to provide respective locking walls thereon to engage within a groove in the rod 11. Each of the bits includes at its butt end a terminal projection or ear 15 which is centrally located with respect to the side edges of the bit and is of reduced width therefrom. The ear 15 curves radially inward and terminates in a radially disposed ear portion which engages or anchors in an annular groove 14 of the rod 1i. The groove 14 is delined on one side by a wall extending from the full diameter of the rod 11 to a diameter less than the reduced portion 11a of the rod, and the other wall of this annular groove has a short radial portion and then is curved as it extends outwardly to merge with the reduced cylindrical portion 11a of the rod. The anchoring ear 15 is curved to conform to the curved portion of the rod 11a.

The curvature of the ear 15 enables satisfactory heat treating of this bent end portion after forming to the desired shape without liability of fracture in heat treating.

In operation, the screw -to be held is placed with its slot embracing the points 12e, then the bit structure is caused by pressure between the screw and the handle to recede Within the handle, the camming pin 13 causing spreading of the points apart so as to be placed in gripping relation within the screw slot. During this spreading apart, there is a deformation of the bit structure within the tube 10, and this deformation is controlled from the ears 15 as a fulcrum. These ears 15 are also pushed against the radial wall formed at the full diameter portion of the rod 11 so that there is no tending of these ears to move out of the groove 14 during this operation.

To restore the screw-holder or screw-starter to its normal position, the rod 11 is pushed from the opposite end with respect to the handle 10 so as to slide the bit structure to its projected position as shown in FIG. 1 where the end bits 12e are again in engaged relation for a screw-holding operation.

While I have shown and described a preferred ernbodiment of the invention, it will be apparent that the yinvention is capable of variation and modication from the form shown so that the scope of the invention should be limited only by the proper scope and interpretation of the claims appended hereto.

I claim:

l. In a screw-holding screw driver of the type cornprising a tubular handle, a bit seating rod slidably mounted Within the handle, a pair of opposed bits engaging said rod for sliding movement therewith and having respective screw-lot engaging ends in normal abutting relation, and a bit expanding pin carried by said handle and engaging between said bits; characterized by a bit formed symmetrically about a longitudinal center line and by a centrally disposed ear at the shank or butt end of each bit terminating in an ear portion defining an end dimension of said bit, said ear portion extending at right angles to the length of said bit and said ear curving gradually from said ear portion to said shank end, said ear being deiined by symmetrical recesses in said shank at either side thereof, said rod having a groove dened on one side by an annular wall perpendicular to the axis thereof for abutting engagement with said ear portions, and defined on the other side by a wall curving to merge with a diameter of said rod, said ear portions of said bits seating in said groove in said rod to hold said bits thereon for telescoping movement therewith with respect to said handle.

2. In a screw-holding screw driver of the type cornprising a tubular handle, a bit seating rod slidably mounted within the handle, a pair of opposed bits engaging said rod for sliding movement therewith and having respective screw-slot engaging ends in normal abutting relation, and a bit expanding pin carried by said handle and engaging between said bits; characterized by a bit formed symmetrically about a longitudinal center line and by symmetrically located anchoring means on each said bit at the shank or butt end thereof and deining an end dimension of said bit, each of said anchoring means being formed inwardly with respect to the shank of the associated bit to provide locking edges at the ends of said symmetrically formed anchoring means, said rod having a groove defined on respective sides thereof by annular walls perpendicular to the axis of said rod for receiving said anchoring means between said annular walls with said Walls engaged by said locking edges to hold said bits on said rod for telescoping movement therewith with respect to said handle, said anchoring means providing a fulcrum located at an end of the associated bit for its expanding movement.

3. In a screw-holding screw driver of the type comprising a tubular handle, a bit seating rod slidably mounted within the handle, a pair of opposed bits engaging said rod for sliding movement therewith and having respective screw-slot engaging ends in normal abutting relation, and a bit expanding pin carried by said handle and engaged between said bits; characterized in that each of said bits is symmetrical about a longitudinal center line and further characterized by symmetrically located anchoring means on each bit at the shank or butt end thereof, each of said anchoring means being formed inwardly with respect to the shank of the associated bit to provide locking edges at the ends of said symmetrically formed anchoring means, said rod having a groove defined on respective sides thereof by annular walls perpendicular to the axis of said rod for receiving said anchoring means between the said annular walls with said Walls engaged by said locking edges to hold said bits on said rod for telescoping movement therewith with respect to the handle, one of said annular Walls extending to the full diameter of said rod, and said anchoring means providing a fulcrum located at an end of the associated bit for -its expanding movement.

References Cited in the file of this patent UNITED STATES PATENTS 2,313,710 Gemmell Mar. 9, 1943 2,404,427 Bloomfield July 23, 1946 2,562,347 Young July 31, 1951 

1. IN A SCREW-HOLDING SCREW DRIVER OF THE TYPE COMPRISING A TUBULAR HANDLE, A BIT SEATING ROD SLIDABLY MOUNTED WITHIN THE HANDLE, A PAIR OF OPPOSED BITS ENGAGING SAID ROD FOR SLIDING MOVEMENT THEREWITH AND HAVING RESPECTIVE SCREW-LOT ENGAGING ENDS IN NORMAL ABUTTING RELATION, AND A BIT EXPANDING PIN CARRIED BY SAID HANDLE AND ENGAGING BETWEEN SAID BITS; CHARACTERIZED BY A BIT FORMED SYMMETRICALLY ABOUT A LONGITUDINAL CENTER LINE AND BY A CENTRALLY DISPOSED EAR AT THE SHANK OR BUTT END OF EACH BIT TERMINATING IN AN EAR PORTION DEFINING AN END DIMENSION OF SAID BIT, SAID EAR PORTION EXTENDING AT RIGHT ANGLES TO THE LENGTH OF SAID BIT AND SAID EAR CURVING GRADUALLY FROM SAID EAR PORTION TO SAID SHANK END, SAID EAR BEING DEFINED BY SYMMETRICAL RECESSES IN SAID SHANK AT EITHER SIDE THEREOF, SAID ROD HAVING A GROOVE DEFINED ON ONE SIDE BY AN ANNULAR WALL PERPENDICULAR TO THE AXIS THEREOF FOR ABUTTING ENGAGEMENT WITH SAID EAR PORTIONS, AND DEFINED ON THE OTHER SIDE BY A WALL CURVING TO MERGE WITH A DIAMETER OF SAID ROD, SAID EAR PORTIONS OF SAID BITS SEATING IN SAID GROOVE IN SAID ROD TO HOLD SAID BITS THEREON FOR TELESCOPING MOVEMENT THEREWITH WITH RESPECT TO SAID HANDLE. 